AudioService: fix mismatch in device volume index for alias streams

Fix VolumeStreamState.setIndex() to force device volume
index update on an alias stream when no specific device volume exists
on the VolumeStreamState of this alias stream.

This prevents asymetric behaviors of setDeviceVolume() and setAllVolumes()
causing some stream types to be muted and
not unmuted if no specific device volume index exist.

Test: make
Test: wipe device, setup wizard, place call and check nofication volume

Bug: 32626244
Change-Id: Idd170aa9f295b0a9533a589e1891a04c05ab2f2f